JP7796573B2 - Bearing device - Google Patents

Description

The present invention relates to a bearing device.

JP 2020-148676 A (Patent Document 1) describes a sensor-equipped bearing (bearing device). The bearing device described in Patent Document 1 includes a rolling bearing, an encoder magnet, a cover, and a coil substrate. The rolling bearing includes an inner ring, an outer ring, and rolling elements.

The direction of the central axis of the inner ring is defined as the axial direction, the direction passing through said central axis and perpendicular to said central axis is defined as the radial direction, and the direction along the circumference of a circle centered on said central axis is defined as the circumferential direction.

The inner ring has an inner ring outer diameter surface. The inner ring outer diameter surface extends in the circumferential direction. The outer ring has an outer ring inner diameter surface. The outer ring inner diameter surface extends in the circumferential direction. The outer ring is arranged outside the inner ring so that the outer ring inner diameter surface faces the inner ring outer diameter surface with a gap between them in the radial direction. The rolling elements are arranged between the inner ring outer diameter surface and the outer ring inner diameter surface. The inner ring is a rotating ring, and the outer ring is a stationary ring. In other words, the inner ring rotates relative to the outer ring.

The encoder magnet has a base material and a magnetic track. The base material is annular and extends in the circumferential direction. The magnetic track is arranged on the main surface of the base material. The magnetic track is magnetized with alternating north and south poles in the circumferential direction. The cover is annular and extends in the circumferential direction. The cover is attached to the outer ring so as to face the magnetic track with a gap in the axial direction.

The coil substrate is disposed inside the cover. The coil substrate is a partial arc extending in the circumferential direction. A yoke and a coil pattern are formed on the coil substrate. The yokes are arranged at intervals in the circumferential direction. The coil pattern extends in the circumferential direction, meandering around the yoke. The coil substrate is attached to the cover so as to face the magnetic track at an interval in the axial direction.

In the bearing device described in Patent Document 1, power is generated by an induced electromotive force in the coil pattern due to changes in magnetic flux from the magnetic track caused by relative rotation of the inner ring with respect to the outer ring.

Japanese Patent Application Laid-Open No. 2020-148676

In the bearing device described in Patent Document 1, the coil pattern on the coil substrate is used as the coil, and the coil patterns formed on multiple layers are connected in parallel or series. However, there is a limit to the number of layers that can be stacked on the coil patterns, so there is room for improvement in the amount of power generated (generated voltage).

The present invention was made in consideration of the problems with the prior art described above. More specifically, the present invention provides a bearing device with a generator that generates a large amount of electricity.

The bearing device of the present invention comprises a rolling bearing having an inner ring, an outer ring, and rolling elements, and a generator that generates electricity in response to the relative rotation of the inner ring with respect to the outer ring. The inner ring has an inner ring outer diameter surface. The outer ring has an outer ring inner diameter surface. The outer ring is disposed radially outward of the inner ring so that the outer ring inner diameter surface faces the inner ring outer diameter surface. The rolling elements are disposed between the inner ring outer diameter surface and the outer ring inner diameter surface. The generator comprises a magnetic ring and a stator. The magnetic ring has a multi-pole magnet in which north and south poles are magnetized alternately in the circumferential direction, and is attached to one of the inner and outer rings. The stator comprises an outer ring, multiple pins, and a coil. The outer ring has an annular portion extending circumferentially, and is attached to the other of the inner and outer rings. The annular portion has an opposing surface that faces the magnetic ring with a gap in the axial direction. The multiple pins are attached to the annular portion so that they are aligned with a gap in the circumferential direction. Each of the multiple pins protrudes axially from the opposing surface toward the magnetic ring. The outer ring and the multiple pins are made of a magnetic material. A coil is wound around each of the multiple pins.

The above-mentioned bearing device may further include a sensor, a wireless communication circuit that wirelessly transmits the output of the sensor, a power supply circuit that rectifies the output of the generator to generate power to be supplied to the sensor and the wireless communication circuit, and a circuit board. The sensor, wireless communication circuit, and power supply circuit may be mounted on the circuit board. The circuit board may be arranged on an opposing surface, avoiding the multiple pins.

In the above-mentioned bearing device, a plurality of holes may be formed in the annular portion. Each of the plurality of pins may be attached to the annular portion by fitting into a corresponding one of the plurality of holes.

In the above-mentioned bearing device, the axial distance between the tip of the pin and the opposing surface may be 10 times or more the axial distance between the multi-pole magnet and the tip of the pin. In the above-mentioned bearing device, the circuit board may be mounted with multiple electrical components that constitute a sensor, a wireless communication circuit, and a power supply circuit. The tip of each of the multiple pins may be located axially farther from the opposing surface than any of the multiple electrical components.

In the above bearing device, the magnetic ring and outer ring may be attached to the inner ring and outer ring, respectively. The inner ring may have a first end face, which is the end face of the inner ring in the axial direction, and an inner ring inner diameter surface. The end of the first end face on the inner ring inner diameter surface side may have a first exposed region, which is annular and extends circumferentially and is exposed from the outer ring. The outer ring may have a second end face, which is the end face of the outer ring in the axial direction, and an outer ring outer diameter surface. The end of the second end face on the outer ring outer diameter surface side may have a second exposed region, which is annular and extends circumferentially and is exposed from the outer ring.

In the above-mentioned bearing device, the magnetic ring and outer ring may be attached to the inner ring and outer ring, respectively. There may be a circumferentially continuous gap between the magnetic ring and the outer ring.

The bearing device of the present invention makes it possible to increase the amount of power generated by a generator.

FIG. 2 is a perspective view of the bearing device 100. FIG. 2 is a front view of the bearing device 100. FIG. 2 is a cross-sectional view of the bearing device 100. FIG. 2 is an exploded perspective view of the bearing device 100. 2 is a schematic cross-sectional view of the bearing device 100 in which the magnetic ring 30 and the stator 40 are linearly developed. FIG. 1 is a perspective view of a bearing device 100 in which the rolling bearing 10 and the magnetic ring 30 are not shown. 1 is a cross-sectional view showing an example of use of the bearing device 100. FIG. 10 is a schematic cross-sectional view of a magnetic ring 30 and a stator 40 in a bearing device 100 according to a modified example, the magnetic ring 30 and the stator 40 being linearly developed.

Details of the embodiment will be described with reference to the drawings. In the following drawings, the same or corresponding parts will be designated by the same reference numerals, and redundant explanations will not be repeated. The bearing device according to the embodiment will be referred to as bearing device 100.

(Configuration of bearing device 100)
The configuration of the bearing device 100 will be described below.

Figure 1 is a perspective view of the bearing device 100. Figure 2 is a front view of the bearing device 100. Figure 3 is a cross-sectional view of the bearing device 100. Figure 3 shows a cross section including the central axis A. Figure 4 is an exploded perspective view of the bearing device 100. As shown in Figures 1, 2, 3, and 4, the bearing device 100 includes a rolling bearing 10 and a generator 20. The generator 20 includes a magnetic ring 30 and a stator 40. The bearing device 100 may further include a circuit board 50.

The rolling bearing 10 has an inner ring 11, an outer ring 12, multiple rolling elements 13, a cage 14, and a seal 15. The rolling bearing 10 is, for example, a deep groove ball bearing. However, the rolling bearing 10 is not limited to this.

The central axis of the inner ring 11 is defined as the central axis A. The direction of the central axis A is defined as the axial direction. The direction passing through the central axis A and perpendicular to the central axis A is defined as the radial direction. The direction along the circumference of a circle centered on the central axis A is defined as the circumferential direction. The inner ring 11 has an end face 11a, an end face 11b (first end face), an inner diameter surface 11c (inner ring inner diameter surface), and an outer diameter surface 11d (inner ring outer diameter surface).

End face 11a and end face 11b are end faces of the inner ring 11 in the axial direction. End face 11a is on one side in the axial direction (left side in Figure 1). End face 11b is the opposite side of end face 11a in the axial direction. In other words, end face 11b is on the other side in the axial direction (right side in Figure 1).

The inner diameter surface 11c extends in the circumferential direction. The inner diameter surface 11c faces the central axis A. One end and the other axial end of the inner diameter surface 11c are connected to the end surface 11a and the end surface 11b, respectively. The outer diameter surface 11d extends in the circumferential direction. The outer diameter surface 11d faces the opposite side from the central axis A. In other words, the outer diameter surface 11d is the opposite surface of the inner diameter surface 11c in the radial direction. One end and the other axial end of the outer diameter surface 11d are connected to the end surface 11a and the end surface 11b, respectively.

The outer diameter surface 11d has a raceway surface 11da. The raceway surface 11da is the portion of the outer diameter surface 11d that contacts the rolling elements 13. The raceway surface 11da extends in the circumferential direction. The raceway surface 11da is located at the center of the outer diameter surface 11d in the axial direction. When viewed in a cross section perpendicular to the circumferential direction, the raceway surface 11da is partially arc-shaped.

The outer diameter surface 11d has a groove 11db. The groove 11db is located at the end of the outer diameter surface 11d on the end face 11b side. The groove 11db extends in the circumferential direction.

The outer ring 12 has an end face 12a, an end face 12b (second end face), an inner diameter surface 12c (outer ring inner diameter surface), and an outer diameter surface 12d (outer ring outer diameter surface). End face 12a and end face 12b are end faces of the outer ring 12 in the axial direction. End face 12a is on one side in the axial direction. End face 12b is the surface opposite end face 12a in the axial direction. In other words, end face 12b is on the other side in the axial direction.

The inner diameter surface 12c extends in the circumferential direction. The inner diameter surface 12c faces the central axis A. One end and the other axial end of the inner diameter surface 12c are connected to the end surface 12a and the end surface 12b, respectively. The outer ring 12 is disposed outside the inner ring 11 so that the inner diameter surface 12c faces the outer diameter surface 11d with a gap between them. The outer diameter surface 12d extends in the circumferential direction. The outer diameter surface 12d faces the opposite side from the central axis A. In other words, the outer diameter surface 12d is the radially opposite surface of the inner diameter surface 12c. One end and the other axial end of the outer diameter surface 12d are connected to the end surface 12a and the end surface 12b, respectively.

The inner diameter surface 12c has a raceway surface 12ca. The raceway surface 12ca is the portion of the inner diameter surface 12c that contacts the rolling elements 13. The raceway surface 12ca extends in the circumferential direction. The raceway surface 12ca is located at the center of the inner diameter surface 12c in the axial direction. When viewed in a cross section perpendicular to the circumferential direction, the raceway surface 12ca has a partial arc shape.

The inner diameter surface 12c has grooves 12cb and 12cc. Groove 12cb is located at the end of the inner diameter surface 12c on the end face 12a side. Groove 12cb extends in the circumferential direction. Groove 12cb is located between the raceway surface 12ca and the end face 12a in the axial direction. Groove 12cc is located at the end of the inner diameter surface 12c on the end face 12b side. Groove 12cc extends in the circumferential direction.

The rolling elements 13 are spherical. They are arranged between the outer diameter surface 11d and the inner diameter surface 12c. More specifically, they are arranged between the raceway surface 11da and the raceway surface 12ca. The rolling elements 13 are arranged at intervals in the circumferential direction. The cage 14 is arranged between the outer diameter surface 11d and the inner diameter surface 12c. The cage 14 holds the rolling elements 13 so that the interval between two adjacent rolling elements 13 is within a certain range. The portion of the cage 14 that holds the rolling elements 13 is connected on the other axial side and is open on one axial side.

Seal 15 is annular and extends circumferentially. The outer peripheral edge of seal 15 is inserted into groove 12cb. The inner peripheral edge of seal 15 contacts seal groove 11dc formed in outer diameter surface 11d. The inner peripheral edge of seal 15 may face seal groove 11dc with a gap between them. The space between outer diameter surface 11d and inner diameter surface 12c is called the bearing space. One axial side of the bearing space is closed by seal 15. A lubricant is sealed in the bearing space.

The magnetic ring 30 has a core 31 and a multi-pole magnet 32. The core 31 has a cylindrical portion 31a and an annular portion 31b. The cylindrical portion 31a is cylindrical and extends in the axial direction. The cylindrical portion 31a is fitted into groove 11db on its inner diameter surface. This attaches the core 31 (magnetic ring 30) to the inner ring 11. The annular portion 31b is annular and extends in the circumferential direction. The annular portion 31b protrudes radially outward from one axial end of the cylindrical portion 31a.

The multi-pole magnet 32 is arranged on the surface of the annular portion 31b facing the other side in the axial direction. The multi-pole magnet 32 is made, for example, from rubber mixed with magnetic powder. The multi-pole magnet 32 is vulcanized and bonded to the annular portion 31b. The multi-pole magnet 32 is magnetized with alternating north and south poles in the circumferential direction.

The stator 40 has an outer ring 41, multiple pins 42, a bobbin 43, and a coil 44. The outer ring 41 is made of a magnetic material. For example, the outer ring 41 is made of silicon steel, carbon steel, martensitic stainless steel, ferritic stainless steel, etc.

The outer ring 41 has an annular portion 41a, a cylindrical portion 41b, and a cylindrical portion 41c. The annular portion 41a is annular and extends circumferentially. The cylindrical portion 41b is cylindrical and extends from the radially inner end of the annular portion 41a to one side in the axial direction. The cylindrical portion 41b faces the magnetic ring 30 in the axial direction, for example. It is preferable that there is a gap between the cylindrical portion 41b and the magnetic ring 30. This gap is continuous in the circumferential direction. The cylindrical portion 41b may face the end face 11b. In this case, there is a gap between the cylindrical portion 41b and the end face 11b that is continuous in the circumferential direction. This gap is, for example, 1 mm or less. The cylindrical portion 41c is cylindrical and extends from the radially outer end of the annular portion 41a to one side in the axial direction. The cylindrical portion 41c is fitted into the groove 12cc on its outer diameter surface. This allows the outer ring 41 (stator 40) to be attached to the outer ring 12.

The annular portion 41a has a first surface 41aa (opposing surface) and a second surface 41ab. The first surface 41aa and the second surface 41ab are end surfaces of the annular portion 41a in the axial direction. The first surface 41aa faces one side in the axial direction. The first surface 41aa faces the magnetic ring 30 (multi-pole magnet 32) with a gap in the axial direction. The second surface 41ab faces the other side in the axial direction. In other words, the second surface 41ab is the surface opposite the first surface 41aa in the axial direction.

Multiple holes 41ac are formed in the annular portion 41a. The holes 41ac penetrate the annular portion 41a in the thickness direction (i.e., the axial direction). The multiple holes 41ac are arranged at intervals in the circumferential direction. Note that the holes 41ac do not have to penetrate the annular portion 41a as long as they can fit the pins 42 described below.

The outer diameter of the outer ring 41 (the outer diameter of the tubular portion 41c) is preferably smaller than the outer diameter of the outer ring 12. Furthermore, the inner diameter of the outer ring 41 (the inner diameter of the tubular portion 41b) is preferably larger than the inner diameter of the inner ring 11. Therefore, the end of the end face 11b on the inner diameter surface 11c side has a ring-shaped region (first exposed region) that extends circumferentially and is exposed from the outer ring 41, and the end of the end face 12b on the outer diameter surface 12d side has a ring-shaped region (second exposed region) that extends circumferentially and is exposed from the outer ring 41.

The pins 42 are made of a magnetic material. For example, the pins 42 are made of silicon steel, carbon steel, martensitic stainless steel, ferritic stainless steel, etc. The pins 42 may be made of the same material as the outer ring 41, or may be made of a different material than the outer ring 41. The pins 42 are, for example, cylindrical. The pins 42 may also be prismatic. The pitch between two adjacent pins 42 is, for example, equal to the pitch between two adjacent magnetic poles of the multi-pole magnet 32.

The pins 42 are attached to the annular portion 41a so as to be spaced apart in the circumferential direction. The pins 42 are preferably attached to the annular portion 41a by being fitted into the holes 41ac. The pins 42 may be attached to the annular portion 41a by press-fitting, bonding, laser welding, or a combination of these. The pins 42 protrude axially from the first surface 41aa toward the magnetic ring 30 (multi-pole magnet 32). The tips of the pins 42 are spaced apart axially from the magnetic ring 30 (multi-pole magnet 32).

A bobbin 43 is passed through the pin 42. A coil 44 is wound around the outer circumferential groove of the bobbin 43. The coil 44 may be wound directly around the pin 42 without using the bobbin 43. It is preferable that the coil 44 wraps around the pin 42 multiple times. The winding direction of the coil 44 around one pin 42 is opposite to the winding direction of the coil 44 around another pin 42 adjacent to that pin 42 in the circumferential direction. The coils 44 wound around each of the multiple pins 42 are connected in series or parallel.

The axial distance between the tip of the pin 42 and the first surface 41aa is defined as the first distance. The axial distance between the tip of the pin 42 and the multi-pole magnet 32 is defined as the second distance. It is preferable that the first distance be at least 10 times the second distance.

Figure 5 is a schematic cross-sectional view of the magnetic ring 30 and stator 40 in the bearing device 100, linearly unfolded. As shown in Figure 5, magnetic flux (see arrows in Figure 5) emitted from the north pole of the multi-pole magnet 32 enters the outer ring 41 (annular portion 41a) from one pin 42, passes through another pin 42 adjacent to that pin 42 in the circumferential direction, and returns to the south pole of the multi-pole magnet 32. As the magnetic ring 30 rotates, the positions of the north and south poles of the multi-pole magnet 32 are swapped, reversing the direction of the magnetic flux. The alternating magnetic field generated in this way generates an alternating voltage between both ends of the coil 44.

As shown in Figures 1, 2, 3, and 4, the circuit board 50 is disposed on the first surface 41aa. The circuit board 50 is disposed so as to avoid the multiple pins 42. From another perspective, the circuit board 50 is positioned so as not to overlap the multiple pins 42 when viewed in the axial direction. An insulating sheet (not shown) may be disposed between the circuit board 50 and the first surface 41aa. The circuit board 50 is attached to the annular portion 41a using, for example, screws, adhesive, etc.

Figure 6 is a perspective view of the bearing device 100, with the rolling bearing 10 and magnetic ring 30 not shown. As shown in Figure 6, the circuit board 50 has terminals 50a and 50b. One end and the other end of the coil 44 are connected to terminals 50a and 50b, respectively. A power supply circuit 51, a sensor 52, and a wireless communication circuit 53 are mounted on the circuit board 50.

The power supply circuit 51 is connected to terminals 50a and 50b by wiring (not shown) formed on the circuit board 50. The output (AC) of the generator 20 (coil 44) is rectified in the power supply circuit 51 to become DC power. The power supply circuit 51 is connected to the sensor 52 and wireless communication circuit 53 by wiring (not shown) formed on the circuit board 50. This supplies the DC power to the sensor 52 and wireless communication circuit 53, driving them.

Sensor 52 monitors the condition of rolling bearing 10. There may be multiple sensors 52, for example. In the example shown in FIG. 5, sensors 52 are acceleration sensor 52a and temperature sensor 52b. Sensors 52 (acceleration sensor 52a, temperature sensor 52b) are connected to wireless communication circuit 53 by wiring (not shown) formed on circuit board 50. As a result, the output of sensor 52 (acceleration sensor 52a, temperature sensor 52b) is transmitted to wireless communication circuit 53. Wireless communication circuit 53 wirelessly transmits the output from sensor 52 from an antenna (not shown).

The tip of the pin 42 is located farther from the first surface 41aa than any of the electrical components that make up the power supply circuit 51, sensor 52, and wireless communication circuit 53. From another perspective, the height of the pin 42 is greater than the maximum height of the electrical components that make up the power supply circuit 51, sensor 52, and wireless communication circuit 53.

Although not shown, a resin material or the like may be applied to the surface of the circuit board 50 to protect the surface. Furthermore, although not shown, a resin sealant may be filled into the internal space of the outer ring 41 to protect the surface of the circuit board 50. The fill height of this sealant is limited to the height of the cylindrical portion 41b.

Figure 7 is a cross-sectional view showing an example of how the bearing device 100 is used. Figure 7 shows a cross section including the central axis A. As shown in Figure 7, the shaft 110 has an end 110a. End 110a is the end of the shaft 110 on the other side in the axial direction (the right side in Figure 7). The outer diameter of end 110a is smaller than the outer diameter of the portion of the shaft 110 that is connected to end 110a. In other words, a step is formed on the outer diameter surface of the shaft 110 between end 110a and the portion of the shaft 110 that is connected to end 110a.

The inner diameter surface 11c is fitted onto the outer diameter surface of the end portion 110a so that the end surface 11a contacts this step. A nut 111 and a spacer 112 are attached to the end portion 110a. The nut 111 is threaded onto the end portion 110a. The spacer 112 is positioned between the nut 111 and the inner ring 11 and contacts the first exposed area of the end surface 11b. This attaches the inner ring 11 to the shaft 110.

The housing 120 has an end 120a. The end 120a is the end of the housing 120 on the other axial side. The inner diameter of the end 120a is larger than the inner diameter of the portion of the housing 120 that is connected to the end 120a. In other words, a step is formed on the inner diameter surface of the housing 120 between the end 120a and the portion of the housing 120 that is connected to the end 120a.

The outer diameter surface 12d is fitted to the inner diameter surface of the end portion 120a so that the end surface 12a contacts this step. A lid 121 is attached to the other axial end of the housing 120. The lid 121 contacts the second exposed area of the end surface 12b. In this way, the outer ring 12 is attached to the housing 120.

(Effects of bearing device 100)
The effects of the bearing device 100 will be described below.

In the bearing device 100, the outer ring 41 not only attaches the stator 40 to the rolling bearing 10, but also functions as part of the yoke of the stator 40. As a result, the bearing device 100 does not require a separate part to secure the stator 40, allowing for a reduction in the number of parts and a more compact design.

In the bearing device 100, the pin 42 is attached to the annular portion 41a by fitting into the hole 41ac, making it easy to position the pin 42 for installation. Furthermore, since a jig for installing the pin 42 is no longer required, the efficiency of the work of installing the pin 42 is also improved.

In the bearing device 100, the first distance is at least 10 times the second distance, which makes it difficult for magnetic flux from the multi-pole magnet 32 to leak to the first surface 41aa. Therefore, the bearing device 100 reduces leakage magnetic flux, making it possible to increase the power generation voltage of the generator 20. As a result, the circuit board 50 (power supply circuit 51, sensor 52, wireless communication circuit 53) can be driven stably even in the low-speed rotation region where the rotation speed of the inner ring 11 is low.

In the bearing device 100, the tip of the pin 42 is located farther from the first surface 41aa than any of the electrical components that make up the power supply circuit 51, sensor 52, and wireless communication circuit 53, thereby avoiding contact between the magnetic ring 30 and these electrical components.

In the bearing device 100, the inner ring 11 can be attached to the shaft 110 using the nut 111 and spacer 112, with the first exposed area of the end face 11b, and the outer ring 12 can be attached to the housing 120 using the lid 121, with the second exposed area of the end face 12b. This allows the bearing device 100 to be used without modifying the structure of the shaft 110 and housing 120. Furthermore, because the bearing device 100 is attached to the shaft 110 and housing 120 in the manner described above, it can be mounted compactly in the axial direction.

In the bearing device 100, there is a gap between the cylindrical portion 41b and the magnetic ring 30 (or between the cylindrical portion 41b and the end face 11b), which allows radio waves from the antenna of the wireless communication circuit 53 to be emitted to the outside through this gap.

(Variation 1)
8 is a schematic cross-sectional view of the magnetic ring 30 and the stator 40 in a bearing device 100 according to a modified example, linearly developed. As shown in Fig. 8, the pitch between two adjacent pins 42 may be larger than the pitch between two adjacent magnetic poles of the multi-pole magnet 32. This makes it possible to accommodate an increase in the number of magnetic poles magnetized in the multi-pole magnet 32.

(Variation 2)
A hole 41ad (not shown) may be formed in the annular portion 41a. The hole 41ad is located opposite the antenna of the wireless communication circuit 53. This allows radio waves from the antenna of the wireless communication circuit 53 to be emitted to the outside through the hole 41ad. The hole 41ad may be plugged with a non-metallic material (e.g., a resin material).

The gap between the cylindrical portion 41b and the magnetic ring 30 (or between the cylindrical portion 41b and the end face 11b) has a labyrinth seal structure, which can prevent foreign matter from entering the inside of the generator 20. Although not shown, the gap between the cylindrical portion 41b and the magnetic ring 30 (or between the cylindrical portion 41b and the end face 11b) may be sealed with a rubber material or the like to prevent foreign matter from entering the inside of the generator 20.

Although the embodiments of the present invention have been described above, the above-described embodiments can be modified in various ways. Furthermore, the scope of the present invention is not limited to the above-described embodiments. The scope of the present invention is defined by the claims, and is intended to include all modifications that are equivalent in meaning to and within the scope of the claims.

10 Rolling bearing, 11 Inner ring, 11a, 11b End face, 11c Inner diameter surface, 11d Outer diameter surface, 11da Raceway surface, 11db Groove, 11dc Seal groove, 12 Outer ring, 12a, 12b End face, 12c Inner diameter surface, 12ca Raceway surface, 12cb, 12cc Groove, 12d Outer diameter surface, 13 Rolling element, 14 Cage, 15 Seal, 20 Generator, 30 Magnetic ring, 31 Core, 31a Cylindrical portion, 31b Annular portion, 32 Multi-pole magnet, 40 Stator, 41 Outer ring, 41a Annular portion, 41aa First surface, 41ab Second surface, 41ac, 41ad Hole, 41b, 41c Cylindrical portion, 42 Pin, 43 Bobbin, 44 Coil, 50 Circuit board, 50a, 50b Terminal, 51 Power supply circuit, 52 Sensor, 52a Acceleration sensor, 52b Temperature sensor, 53 Wireless communication circuit, 100 Bearing device, 110 Shaft, 110a End, 111 Nut, 112 Spacer, 120 Housing, 120a End, 121 Cover, A Central shaft.

Claims (7)

a rolling bearing having an inner ring, an outer ring, and rolling elements;
a generator that generates electricity in accordance with the relative rotation of the inner ring with respect to the outer ring,
the inner ring has an inner ring outer diameter surface,
the outer ring has an outer ring inner diameter surface,
the outer ring is disposed radially outward of the inner ring such that the outer ring inner diameter surface faces the inner ring outer diameter surface,
the rolling elements are disposed between the outer diameter surface of the inner ring and the inner diameter surface of the outer ring,
The generator includes a magnetic ring and a stator.
the magnetic ring has a multi-pole magnet in which north and south poles are alternately magnetized in a circumferential direction, and is attached to one of the inner ring and the outer ring;
The stator has an outer ring, a plurality of pins, and a coil,
the outer ring has an annular portion extending in the circumferential direction and is attached to the other of the inner ring and the outer ring,
the annular portion has an opposing surface that faces the magnetic ring with a gap in the axial direction,
the plurality of pins are attached to the annular portion so as to be arranged at intervals in the circumferential direction,
each of the plurality of pins protrudes from the opposing surface toward the magnetic ring in the axial direction;
the outer ring and the plurality of pins are made of a magnetic material,
the coil is wound around each of the plurality of pins;
The outer ring and the coil are disposed outside the rolling bearing . A sensor,
a wireless communication circuit for wirelessly transmitting an output of the sensor;
a power supply circuit that rectifies the output of the generator to generate power supplied to the sensor and the wireless communication circuit;
a circuit board;
the sensor, the wireless communication circuit, and the power supply circuit are mounted on the circuit board;
The bearing device according to claim 1 , wherein the circuit board is disposed on the opposing surface so as to avoid the plurality of pins. The annular portion has a plurality of holes formed therein,
3. The bearing device according to claim 1, wherein each of the plurality of pins is attached to the annular portion by being fitted into each of the plurality of holes. A bearing device according to any one of claims 1 to 3, wherein the axial distance between the tip of each of the pins and the opposing surface is at least 10 times the axial distance between the multi-pole magnet and the tip of each of the pins. a plurality of electrical components that constitute the sensor, the wireless communication circuit, and the power supply circuit are mounted on the circuit board;
3. The bearing device according to claim 2, wherein a tip of each of the plurality of pins is located farther from the opposing surface in the axial direction than any of the plurality of electrical components. the magnetic ring and the outer ring are attached to the inner ring and the outer ring, respectively;
the inner ring has a first end surface that is an end surface of the inner ring in the axial direction, and an inner ring inner diameter surface,
an annular first exposed region extending in the circumferential direction and exposed from the outer ring is present at an end of the first end surface on the inner diameter surface side of the inner ring,
the outer ring has a second end face that is an end face of the outer ring in the axial direction, and an outer ring outer diameter surface,
A bearing device according to any one of claims 1 to 5, wherein an end portion of the second end face on the outer diameter surface side of the outer ring has a second exposed area that is annular and extends in the circumferential direction and is exposed from the outer ring. the magnetic ring and the outer ring are attached to the inner ring and the outer ring, respectively;
The bearing device according to any one of claims 1 to 5, wherein a gap that is continuous in the circumferential direction is present between the magnetic ring and the outer ring or the inner ring.